Bug fixes vis-a-vis current Firefox

[number61971]

The ua.version comparison needs to be a float comparison, not string. (I.e., because current FF versions like "18.0" compare as < "2.0").

I also removed the explicit "font-size: 100px" setting because, in my own tests, that broke the element substitution in Firefox. The clickable area never matched the size of the replacement element unless I removed that font-size.

[hleinone]

That font-size was there because of the problems mentioned in here

That button looks just like the comp! But there is just one problem…the button is not clickable in certain areas in some browsers. So after talking with Jason about the problem, he suggested making the font size of the input really big. And it worked!

I'll have to test it and see if I can find browsers that are affected by the issue mentioned, and then decide if those browsers are relevant anymore.

Thank you for your fixes!